There should be a recessed spot in the front storage area specifically designed to hold a marine fire extinguisher. It should also have a bracket with a rubber strap to hold it in place.
It seems there is suppose to be a tub that inserts in the front storage compartment I am missing. It looks like there is a mounting area in the tub for the fire extinguisher
Yes the tub seals waterproof and the whole thing pulls out. It’s second job is to help keep your ski from sinking if the the back end fills with water. Owners manual says don’t operate the ski without the tub installed.